The present disclosure describes systems and techniques relating to wired communication channels, such as telephone lines in a bundled telephone cable.
G.hn is a home networking standard developed by ITU (International Telecommunications Union). The G.hn standard describes a multi-node network (similar to a WiFi network) that shares a channel (power line, phone line or coax cable). A network is known as a “domain” in the standard. A domain is controlled by a single node called Domain Master (DM). The Domain Master is in charge of coordinating the transmissions of all the nodes in the network (scheduling) to avoid collisions in the channel and guarantee a required level of quality of service (QoS) to the traffic conveyed in the domain. Each node can communicate with any of the other nodes of the domain (multi-point to multi-point communications).
On the other hand, the architecture of DSL (Digital Subscriber Line) phone line access applications is different. The architecture of DSL is based on a pair of nodes that communicate with each other: one node is placed at the customer side, referred to as the CPE (Customer Premises Equipment), and the other node is an operator node placed at the telephone company side, typically along with other operator nodes in a DSLAM (DSL Access Multiplexer). Since several operator nodes are typically collocated at the DSLAM, the operator nodes have the potential to interfere with each other, as phone lines run together from the DSLAM to each of the customer premises and can suffer from crosstalk among the phone lines. There are two sources of interference: NEXT (near end crosstalk) interference from one operator node to another operator node, and FEXT (far end crosstalk) interference from one operator node to the CPEs of other lines (or the other way around; interference from one CPE to the operator nodes of other lines). DSL standards have developed different ways of overcoming this interference. In addition, improvements have been proposed for DSL to increase its speed; such proposals are often referred to as VDSL.